超大容量氢同位素色谱分离系统的概念设计

在多年从事色谱分离氢同位素技术研究的基础上,设计了一套超大容量氢同位素分离系统,包括系统的总体设计,以配气及纯化、三级色谱柱、气体流路及自动控制和载气回收为主的单元设计,以及调试实验方案设计。该系统的特点是可以根据氢同位素分离解吸谱图的信息比较直接地计算出解吸过程的动力学参数,即在实验数据的支持和适当的假设条件（平衡再吸附、均匀表面）下,依靠解吸速率方程、形状参数和解吸活化能的计算便可比较系统地描述其复杂的动力学过程。在以前的工作中,虽然已经证实了采用5A分子筛柱在77 K的低温下,可以连续富集氢 氘混合气中的氘、天然氢中的氘,甚至含氚重水中的氚的可行性,但本工作仅是初步的概念设计,其可行性还须通过实验结果来验证。     

Influence of argon and hydrogen ions energy on the structure of a-Si:H prepared by ion-beam-assisted evaporation

Hydrogenated amorphous silicon films were deposited by ion-beam-assisted evaporation onto substrates maintained at 200°C. The gases introduced in the ion source were pure hydrogen or an argon–hydrogen mixture. The energy of the ions was varied by biasing the substrate. By combined infrared spectrometry and thermal desorption spectrometry experiments, it is inferred that the bombardment of the growing a-Si:H film by 300 eV hydrogen ions or 20 eV argon ions produces a densification of the material.     

Ti-Mo合金的吸放氢动力学

采用磁悬浮熔炼法制备了5种不同组成的TiMo_x（x=0.03, 0.12, 0.25, 0.50, 1.00，原子比）固溶体合金，用定容变压法测试了其在不同温度范围内的吸放氢动力学性能。研究结果表明，合金的吸放氢动力学可以按一级反应来描述，决速步骤为氢原子在合金晶格中的扩散。相同温度下，不同组成样品的吸氢容量随Mo含量的增加而降低。合金的吸氢活性随Mo含量增加先增强后减弱，氢化物的稳定性随Mo含量的增加而降低。     

氢同位素色谱分离柱程序升温解吸的理论研究

在物理吸附动力学和多年色谱分离氢同位素实验的基础上,针对氢同位素与5A分子筛表面的程序升温解吸过程开展了理论研究,推导了一级无再吸附、一级再吸附、二级无再吸附和二级再吸附四种条件下的解吸速率方程,并通过计算形状参数和解吸活化能对解吸过程的动力学特征加以鉴别。     

Effect of induced damage on hydrogen isotope retention of F82H with impurity layer

The effects of induced damage on hydrogen isotope retention in F82H with or without thermal oxidation were investigated using thermal desorption spectroscopy. To induce damage and modify the surface, glow discharge pre-irradiated Ar⁺ ions was examined. In non-oxidized samples, the amount of desorbed deuterium increased with Ar⁺ ion fluence. Oxygen depletion in the surface layer of non-oxidized samples from the Ar⁺ ion irradiation, which resulted in bulk diffusion of deuterium, is responsible for the increase in deuterium retention. A comparison between non-oxidized and oxidized samples clearly indicated that the surface oxide layer greatly influenced deuterium retention/desorption behaviors of F82H.     

H and D depth profiles in implanted and laser-annealed beryllium

The thermodynamic properties of H and D implanted in Be to different fluences have been investigated by laser flash desorption. From the evolution of the H and D depth profiles following laser annealing, different detrapping/diffusion processes in matter are proposed. The experimental results were compared to those obtained from a finite element time resolved simulation code. Two different processes depending on the H or D fluence can be inferred: at low fluence, a 1.7 eV/molecule detrapping energy and a fairly high effective diffusion coefficient have to be involved, while at high fluence the detrapping energy is ≤1 eV/molecule and an extremely rapid migration have to be considered. The transition between these two regimes corresponds approximately to the fluence for which blistering becomes detectable.     

两种热解吸动力学测试方法的比较

以氢化钛热解吸反应为研究对象,用升温法（初压为零）和恒温法（初压不为零）两种不同的方法,在高真空金属系统上分别测定氢化钛在恒容体系和350～550℃范围内解吸氢的p-t曲线,并应用反应速率分析方法计算解吸反应在不同温度下的速率常数。实验测得氢化钛升温法热解吸和恒温法热解吸的表观活化能分别为（22.1±2.5）和（27.1±0.4）kJ•mol^－1。经分析,用恒温法测得的表观活化能较为准确。     

First-principles energy and vibration spectrum simulations of Cr/V interacting with H in W-based alloy in a fusion reactor

We perform first-principles total energy and vibration spectrum calculations to study the effect of Cr/V on the H formation and diffusion at temperature range 300–2100 K in dilute W–Cr/W–V alloy. Temperature and H chemical potential are two important factors to affect the H formation energy and migrating energy. The H formation energy referring to the static/temperature-dependent H chemical potential decreases/increases with the temperature. At each given temperature, the presence of Cr in W reduces the H formation energy, while the existence of V in W has little effect on the H formation energy. The diffusion energy barrier and pre-exponential factor strongly depend on the temperature and increase with the temperature from 300 to 2100 K. Both Cr and V additions in W has a large consequences on H migrating energy. The energy barriers at any given temperature can be reduced by ～0.05 and 0.10 eV in W–Cr and W–V alloys, respectively. The current study reveals that vibration free energy plays a decisive role in the formation energy and migrating energy of H with the temperature, while the thermal expansion energy has little influence on the H formation energy and migrating energy with the temperature.     

载钯硅藻土的制备及其吸放氢性能研究

采用PdCl2溶液以浸渍还原法制备了载钯硅藻土复合材料(Pd/K),并对Pd/K复合材料中钯的分布状态,以及Pd/K复合材料的p-C-T曲线、热力学、动力学及循环吸放氢性能进行了研究。结果表明:与纯钯相比,载钯硅藻土样品吸氢量有所降低,吸放氢平台压稍有升高,平台斜率增大,其吸氢速率比纯钯的高1倍以上;吸放氢焓变值降低,熵变值升高。经2000次吸放氢循环后,载钯硅藻土的样品饱和吸氢量和吸氢速率未改变,粉化率为3.6%(质量分数)。     

Sorption and desorption behavior of hydrogen isotopes from tungsten deposits caused by deuterium gas or deuterium plasma exposure

To understand the behavior of hydrogen isotopes in deposits formed on plasma-facing wall is an important issue for development of a fusion reactor. In this study, sorption/desorption behaviors of hydrogen isotopes when tungsten deposits were exposed to deuterium gas or deuterium plasma at 300 °C were investigated. Samples of tungsten deposits were produced by the sputtering method using hydrogen plasma. After deuterium gas exposure or deuterium plasma exposure, the desorption behavior of hydrogen isotopes from the deposit was observed by the thermal desorption spectroscopy method. It was found that not a small amount of deuterium is retained in tungsten deposit by not only the plasma exposure but also the gas exposure while the amount of hydrogen incorporated in the deposit during sputter-deposition process is reduced. The amount of deuterium retained in the deposit by the plasma exposure was larger than that by the gas exposure in the experimental conditions in this work. The amount of hydrogen left after deuterium plasma exposure was larger than that after deuterium gas exposure.     

Conversion of coalbed methane surrogate into hydrogen and graphene sheets using rotating gliding arc plasma

The use of atmospheric rotating gliding arc(RGA) plasma is proposed as a facile, scalable and catalyst-free approach to synthesizing hydrogen(H_2) and graphene sheets from coalbed methane(CBM). CH_4 is used as a CBM surrogate. Based on a previous investigation of discharge properties, product distribution and energy efficiency, the operating parameters such as CH_4 concentration, applied voltage and gas flow rate can effectively affect the CH_4 conversion rate,the selectivity of H_2 and the properties of solid generated carbon. Nevertheless, the basic properties of RGA plasma and its role in CH_4 conversion are scarcely mentioned. In the present work, a 3D RGA model, with a detailed nonequilibrium CH_4/Ar plasma chemistry, is developed to validate the previous experiments on CBM conversion, aiming in particular at the distribution of H_2 and other gas products. Our results demonstrate that the dynamics of RGA is derived from the joint effects of electron convection, electron migration and electron diffusion, and is prominently determined by the variation of the gas flow rate and applied voltage. Subsequently,a combined experimental and chemical kinetical simulation is performed to analyze the selectivity of gas products in an RGA reaction, taking into consideration the formation and loss pathways of crucial targeted substances(such as CH_4, C_2H_2, H_2 and H radicals) and corresponding contribution rates. Additionally, the effects of operating conditions on the properties of solid products are investigated by scanning electron microscopy(SEM) and Raman spectroscopy. The results show that increasing the applied voltage and decreasing CH_4 concentration will change the solid carbon from its initial spherical structure into folded multilayer graphene sheets, while the size of the graphene sheets is slightly affected by the change in gas flow rate.     

Effect of Gas Sources on the Deposition of Nano-Crystalline Diamond Films Prepared by Microwave Plasma Enhanced Chemical Vapor Deposition

Nano-crystalline diamond (NCD) films were deposited on silicon substrates by a microwave plasma enhanced chemical vapor deposition (MPCVD) reactor in C2H5OH/H2 and CH4/H2/O2 systems, respectively, with a constant ratio of carbon/hydrogen/oxygen. By means of atomic force microscopy (AFM) and X-ray diffraction (XRD), it was shown that the NCD films deposited in the C2H5OH/H2 system possesses more uniform surface than that deposited in the CH4/H2/O2 system. Results from micro-Raman spectroscopy revealed that the quality of the NCD films was different even though the plasmas in the two systems contain exactly the same proportion of elements. In order to explain this phenomenon, the bond energy of forming OH groups, energy distraction in plasma and the deposition process of NCD films were studied. The experimental results and discussion indicate that for a same ratio of carbon/hydrogen/oxygen, the C2H5OH/H2 plasma was beneficial to deposit high quality NCD films with smaller average grain size and lower surface roughness.     

热处理对LaNi4.25Al0.75/SiO2复合材料储氢特性的影响

采用气相二氧化硅法制备了LaNi_4.25Al_0.75/SiO₂复合材料。研究了该复合材料经不同温度（473～1 073 K）热处理后的相组成、形貌及吸放氢p-C-T曲线、吸氢动力学性能和吸放氢循环性能。结果表明,随着热处理温度的升高,LaNi_4.25Al_0.75/SiO₂复合材料吸氢量减少,平台压升高,平台斜率略有增加,而动力学性能并无显著变化。经60次吸放氢循环后,经不同温度热处理后的样品均未出现粉化现象,且与未循环样品储氢性能基本保持一致。     

乙醇为碳源的低氢常压CVD法制备石墨烯薄膜及其生长机理研究

以乙醇为碳源,采用低氢常压化学气相沉积(CVD)法在铜基底上制备石墨烯薄膜,并将其成功转移至目标基底。通过SEM、Raman、TEM、选区电子衍射等分析发现,所制备的石墨烯薄膜结构完整、质量良好。通过设计实验,观察和分析了石墨烯薄膜生长过程中主要阶段的形貌特征及生长机理。结果表明,乙醇高温分解出的碳原子在铜基底表面聚集形核,形成的原始晶粒逐渐长大为岛状晶畴直至形成树枝状薄片,并在生长过程中跨越铜基底表面晶界,最后形成完整的石墨烯薄膜。     

贮氢合金吸氢致应力的实验研究和数学推导

贮氢合金已被广泛用作氚的贮存和增压材料，在吸放氢过程中发生晶格的膨胀和收缩，其非均匀形变对结构容器(贮氢床)的器壁产生应力，材料粉化导致自压实，形成应力集中。采用电阻应变测量法研究了贮氢合金吸放氢循环床体壁应力与循环次数、贮氢容量、壁厚以及装料分额的关系，并从理论上推导了壁应力与贮量的关系。     

High ion-beam induced electron yields from polycrystalline diamond

Extraordinarily high ion-beam induced electron yields are seen from polycrystalline diamond surfaces for high energy H⁺, He⁺ and Ar⁺ ions. This is attributed to the negative electron affinity of the diamond surface. However, the yield decays rapidly with dose, limiting the potential applications. The mechanism for decay is suggested to be electron-stimulated desorption of surface hydrogen, which removes the negative electron affinity responsible for high yields.     

H原子在γ-U(100)表面吸附与扩散的密度泛函研究

采用密度泛函理论方法研究了H原子在γ-U(100)表面的吸附和扩散。结果表明：H原子在γ-U(100)表面的最佳吸附位依次为穴位、桥位和顶位,吸附能分别为2.696、2.597和2.017 eV;H原子在γ-U中的最佳间隙位为四面体间隙,其次是八面体间隙,吸附能分别为1.534 eV和0.991 eV;H原子在铀表面以及近表面层的不同吸附位之间的扩散需克服不同的势垒,相比于间隙位,H原子更倾向于在γ-U(100)表面吸附聚集。     

Laboratory studies of H retention and LiH formation in liquid lithium

Laboratory experiments on H/D retention on liquid lithium followed by thermal desorption spectrometry (TDS) have been performed at Ciemat. Two different experimental set ups were used in order to expose liquid Li to hydrogen gas or to hydrogen glow discharge plasmas at temperatures up to 673 K. In the present work the results concerning the gas phase absorption are addressed. Two different kinetics of absorption were identified from the time evolution of the uptake. Alternate exposures to H₂ and D₂ were carried out in order to study the isotope exchange and its possible use for tritium retention control in Fusion Reactor. Although important differences were found in the absorption kinetics of both species, the total retention seems to be governed by the total sum of hydrogenic isotopes, and only small differences were found in the corresponding TDS spectra, on which evidence of some isotope exchange is observed. The results are discussed in relation to the potential use of liquid lithium walls in a Fusion Reactor.     

LiD与H2O反应机理及动力学

在6-311G（d）水平下,采用微扰理论的MP2方法,研究了LiD与H2O的反应。结果表明,反应存在两个通道：LiD+H2O→LiOH+HD（R1）;LiD+H2O→LiOD+H2（R2）。298K下,两通道的势垒高度分别为9.31和195.08kJ/mol,反应速率常数分别为1.88×1010和3.74×10－26（mol•dm－3）－1•s－1。     

低温循环色谱法分离H_2/HD

低温循环色谱法(CCC)是一种有效的氢同位素分离方式。在升级改造后的低温色谱分离装置上开展了H2/HD体系的分离研究。结果表明:原始氘丰度为1.4×10-4的高纯氢经过CCC 4个流程后,氘丰度达到1.173×10-3;为获得最佳色谱柱柱效,CCC的进样量控制在组分峰的容量因子下降10%时较为合适;CCC的双柱间可互相充当解吸柱与接收柱的角色,在柱结构与程序升温条件相同的前提下,双柱间分离效果的差异可能是进样点的选择和进样压力的不同造成的,与进样时间无关。